Evaluating carbon dioxide emissions in international trade of China

China is the world's largest emitter of carbon dioxide (CO₂). As exports account for about one-third of China's GDP, the CO₂ emissions are related to not only China's own consumption but also external demand. Using the input–output analysis (IOA), we analyze the embodied CO₂ emissions of China's import and export. Our results show that about 3357 million tons CO₂ emissions were embodied in the exports and the emissions avoided by imports (EAI) were 2333 million tons in 2005. The average contribution to embodied emission factors by electricity generation was over 35%. And that by cement production was about 20%. It implies that the production-based emissions of China are more than the consumption-based emissions, which is evidence that carbon leakage occurs under the current climate policies and international trade rules. In addition to the call for a new global framework to allocate emission responsibilities, China should make great efforts to improve its energy efficiency, carry out electricity pricing reforms and increase renewable energy. In particular, to use advanced technology in cement production will be helpful to China's CO₂ abatement.     

Impacts of CO2 emission constraints on technology selection and energy resources for power generation in Bangladesh

This paper examines the impacts of CO₂ emission reduction target and carbon tax on future technologies selection and energy use in Bangladesh power sector during 2005–2035. The analyses are based on a long-term energy system model of Bangladesh using the MARKAL framework. The analysis shows that Bangladesh will not be able to meet the future energy demand without importing energy. However, alternative policies on CO₂ emission constraints reduce the burden of imported fuel, improve energy security and reduce environmental impacts. The results show that the introduction of the CO₂ emission reduction targets and carbon taxes directly affect the shift of technologies from high carbon content fossil-based to low carbon content fossil-based and clean renewable energy-based technologies compared to the base scenario. With the cumulative CO₂ emission reduction target of 10–20% and carbon tax of 2500 Taka/ton, the cumulative net energy imports during 2005–2035 would be reduced in the range of 39–65% and 37%, respectively, compared to the base scenario emission level. The total primary energy requirement would be reduced in the range of 4.5–22.3% in the CO₂ emission reduction targets and carbon tax 2500 Taka/ton scenarios and the primary energy supply system would be diversified compared to the base scenario.     

The forecast of motor vehicle,energy demand and CO2 emission from Taiwan's road transportation sector

The grey forecasting model, GM(1,1) was adopted in this study to capture the development trends of the number of motor vehicles, vehicular energy consumption and CO₂ emissions in Taiwan during 2007–2025. In addition, the simulation of different economic development scenarios were explored by modifying the value of the development coefficient, a, in the grey forecasting model to reflect the influence of economic growth and to be a helpful reference for realizing traffic CO₂ reduction potential and setting CO₂ mitigation strategies for Taiwan. Results showed that the vehicle fleet, energy demand and CO₂ emitted by the road transportation system continued to rise at the annual growth rates of 3.64%, 3.25% and 3.23% over the next 18 years. Besides, the simulation of different economic development scenarios revealed that the lower and upper bound values of allowable vehicles in 2025 are 30.2 and 36.3 million vehicles, respectively, with the traffic fuel consumption lies between 25.8 million kiloliters to 31.0 million kiloliters. The corresponding emission of CO₂ will be between 61.1 and 73.4 million metric tons in the low- and high-scenario profiles.     

Energy demand and carbon emissions under different development scenarios for Shanghai,China

In this paper, Shanghai's CO₂ emissions from 1995 to 2006 were estimated following the IPCC guidelines. The energy demand and CO₂ emissions were also projected until 2020, and the CO₂ mitigation potential of the planned government policies and measures that are not yet implemented but will be enacted or adopted by the end of 2020 in Shanghai were estimated. The results show that Shanghai's total CO₂ emissions in 2006 were 184 million tons of CO₂. During 1995–2006, the annual growth rate of CO₂ emissions in Shanghai was 6.22%. Under a business-as-usual (BAU) scenario, total energy demand in Shanghai will rise to 300 million tons of coal equivalent in 2020, which is 3.91 times that of 2005. Total CO₂ emissions in 2010 and 2020 will reach 290 and 630 million tons, respectively, under the BAU scenario. Under a basic-policy (BP) scenario, total energy demand in Shanghai will be 160 million tons of coal equivalent in 2020, which is 2.06 times that of 2005. Total CO₂ emissions in 2010 and 2020 in Shanghai will be 210 and 330 million tons, respectively, 28% and 48% lower than those of the business-as-usual scenario. The results show that the currently planned energy conservation policies for the future, represented by the basic-policy scenario, have a large CO₂ mitigation potential for Shanghai.     

Coal utilization in industrial boilers in China —a prospect for mitigating CO2 emissions

It is estimated from GEF statistical data for 1991 that more than 500,000 industrial boilers (mostly stoker-fired) in China consume over 400 million tons of coal per year. Each year, because of low boiler efficiency, 75 million tons of coal is wasted and 130 million tons of excess CO₂ are emitted. An analysis of 250 boiler thermal-balance test certificates and 6 field visits in three provinces have shown that: (1) boilers with efficiencies of less than 70% account for 75% of the total boiler-population; (2) the main causes of the low efficiencies are high excess air and unburned carbon in the slag and fly ash. The effect of unburned carbon on CO₂ emission is a balance of positive and negative contributions: while the unburned carbon does not produce CO₂ emissions, its replacement carbon, burned at a low efficiency, contributes to a net increase in CO₂ emissions. It seems from the analysis that the average boiler efficiency can be raised to 73% by relatively simple means, such as the size grading of the coal, improved boiler operating practice and some inexpensive equipment modifications. This could then result in savings each year of 34 million tons of coal and a reduction in CO₂ emissions of 63 million tons at an estimated cost of $10 per ton of CO₂.     

The analysis of CO2 emission reduction using an ExSS model of Guangdong province in China

This paper studied the CO₂ emission scenarios of Guangdong province in 2020 and divided the CO₂ emission increment and reductions into various departments and driving factors. Based on the Extended Snapshot model, two CO₂ emission scenarios, Business as Usual (BaU) and Counter Measure (CM) scenario were constructed. CM scenario was completed by using reduction technical measures to achieve the reduction emission goal. The results showed that the amount of CO₂ emission is less 189 million tonne in 2020 CM scenario than BaU scenario. By decomposing the emission reduction measures in CM scenario, it showed that the main means to reduce CO₂ emissions were the industrial structure adjustment, the advanced energy efficiency and the power sector structure adjustment, and the emission reduction contribution rates were 36.85%, 34.55% and 21.74%, respectively. The analysis results could be recommended to the government to make the low-carbon development policy and path.     

Cost of energy and environmental policy in Portuguese CO2 abatement—scenario analysis to 2020

This paper quantifies the contribution of Portuguese energy policies for total and marginal abatement costs (MAC) for CO₂ emissions for 2020. The TIMES_PT optimisation model was used to derive MAC curves from a set of policy scenarios including one or more of the following policies: ban on nuclear power; ban on new coal power plants without carbon sequestration and storage; incentives to natural gas power plants; and a cap on biomass use. The different MAC shows the policies’ effects in the potential for CO₂ abatement. In 2020, in the most encompassing policy scenario, with all current and planned policies, is possible to abate only up to +35% of 1990 emissions at a cost below 23 € t/CO₂. In the more flexible policy scenarios, it is possible to abate up to −10% of 1990 emissions below the same cost. The total energy system costs are 10–13% higher if all policies are implemented—76 to 101 B€—roughly the equivalent to 2.01–2.65% of the 2005 GDP. Thus, from a CO₂ emission mitigation perspective, the existing policies introduce significant inefficiencies, possibly related to other policy goals. The ban on nuclear power is the instrument that has the most significant effect in MAC.     

Reductions in emissions of local air pollutants and co-benefits of Chinese energy policy: a Shanghai case study

To better understand the reductions in local air pollution that will result from the implementation of current Chinese energy policy, as well as the co-benefit for greenhouse-gas emission reductions, a Shanghai case study was conducted. The MARKAL model was used to forecast energy consumption and emissions of local air pollutants under different energy policy scenarios and also to analyze the associated reductions in CO₂ emissions. The results show that energy policies in Shanghai will significantly reduce SO₂ and PM₁₀ emissions and will also achieve the co-benefit of mitigating the increase of CO₂ emissions. In energy policy scenarios, SO₂ emissions during the period 2000–2020 will maintain the same level as in 2000; and the annual rate of increase of CO₂ emissions will be reduced to 1.1–1.2%, compared with 2.7% under a business-as-usual scenario. The problem for the future will be NO_x emissions, which are projected to increase by 60–70% by 2020, due to expansion of the transportation system.     

Long-term energy savings and greenhouse gas emission reductions in the Swiss residential sector

The aim of this paper is to explore the possibilities to reach two long-term targets regarding energy consumption and greenhouse gas emissions of the Swiss residential building stock: a reduction of the final energy consumption by a factor of 3 and of _CO2${\mathrm{CO}}_2$ emissions by a factor of 5 until 2050. A model is constructed to describe the dynamics of the energy-relevant properties of the residential building stock. Appropriate scenarios are discussed in terms of decisions made during construction or renovation of residential buildings which affect heat demand and determine the energy carriers used for heating and hot water generation. We show that both targets could be reached, although ambitious efforts are necessary. The central element of a successful strategy is to reduce the specific heat demand of existing buildings during renovation and to substitute the heating and hot water systems by less carbon intensive ones. Our results suggest that there is more flexibility to reach the emission target than the energy reduction target.     

The carbon content of Japan–US trade

We analyze the greenhouse gas emissions embodied in trade between Japan and the US, extending the Japanese government's linked Japan–US input–output model to include carbon emission coefficients for each sector. We estimate that in 1995, Japan–US trade reduced US industrial emissions by 14.6 million tons of CO₂-equivalent, and increased emissions in Japan by 6.7 million tons, for a global savings of 7.9 million tons. These quantities are less than one percent of each country's total emissions. Trade with the rest of the world reduced emissions by much larger amounts, roughly four percent of each country's emissions. The sectoral patterns of carbon intensity are strongly correlated between Japan and the US; in addition, greater carbon intensity has a small but significantly positive effect on net exports. Policies that tax or otherwise regulate carbon emissions are needed to discourage this destructive route to competitiveness. However, the most important policy implication may be that US industry could cut its carbon emissions by more than half if it matched the environmental performance of industry in Japan.     

Modelling the UK residential energy sector under long-term decarbonisation scenarios: Comparison between energy systems and sectoral modelling approaches

The UK government has set a groundbreaking target of a 60% reduction in carbon dioxide (CO₂) emissions by 2050. Scenario and modelling assessment of this stringent target consistently finds that all sectors need to contribute to emissions reductions. The UK residential sector accounts for around 30% of the total final energy use and more than one-quarter of CO₂ emissions. This paper focuses on modelling of the residential sector in a system wide energy–economy models (UK MARKAL) and key UK sectoral housing stock models. The UK residential energy demand and CO₂ emission from the both approaches are compared. In an energy system with 60% economy-wide CO₂ reductions, the residential sector plays a commensurate role. Energy systems analysis finds this reduction is primarily driven by energy systems interactions notably decarbonisation of the power sector combined with increased appliance efficiency. The stock models find alternate decarbonisation pathways based on assumptions related to the future building stock and behavioural changes. The paper concludes with a discussion on the assumptions and drivers of emission reductions in different models of the residential energy sector.     

Assessment of CO2 emissions and its reduction potential in the Korean petroleum refining industry using energy-environment models

We assessed potential future CO₂ reduction in the Korean petroleum refining industry by investigating five new technologies for energy savings and CO₂ mitigation using a hybrid SD-LEAP model: crude oil distillation units (CDU), vacuum distillation units (VDU), light gas-oil hydro-desulfurization units (LGO HDS), and the vacuum residue hydro-desulfurization (VR HDS) process. The current and future demand for refining industry products in Korea was estimated using the SD model. The required crude oil input amounts are expected to increase from 139 million tons in 2008 to 154 million tons in 2030 in the baseline scenario. The current and future productivity of the petroleum refining industry was predicted, and this prediction was substituted into the LEAP model which analyzed energy consumption and CO₂ emissions from the refining processes in the BAU scenario. We expect that new technology and alternative scenarios will reduce CO₂ emissions by 0.048% and 0.065% in the national and industrial sectors, respectively.     

Decomposition analysis of CO2 emission in long-term climate stabilization scenarios

To achieve the stabilization of greenhouse gas (GHG) concentrations in the atmosphere, the international community will need to intensify its long-term efforts. Many EU countries have released national long-term scenarios toward 2050, and their ambitious targets for CO₂ emission reduction are aiming at a decrease of more than 50% of today's emission. In April 2004, Japan began a research project on its long-term climate policy. This paper discusses the long-term scenarios in other countries and the medium-term scenarios in Japan to support the development of a Japan's long-term climate stabilization scenario. In this study, CO₂ emission is decomposed with an extended Kaya identity (indexes: CO₂ capture and storage, carbon intensity, energy efficiency, energy intensity, economic activity) and a Reduction Balance Table is developed.     

Study on China's low carbon development in an Economy–Energy–Electricity–Environment framework

Emissions mitigation is a major challenge for China's sustainable development. We summarize China's successful experiences on energy efficiency in past 30 years as the contributions of Energy Usage Management and Integrated Resource Strategic Planning, which are essential for low-carbon economy. In an Economy–Energy–Electricity–Environment (E4) framework, the paper studies the low-carbon development of China and gives an outlook of China's economy growth, energy–electricity demand, renewable power generation and energy conservation and emissions mitigation until 2030. A business-as-usual scenario is projected as baseline for comparison while low carbon energy and electricity development path is studied. It is defined as low carbon energy/electricity when an economy body manages to realize its potential economic growth fueled by less energy/electricity consumption, which can be characterized by indexes of energy/electricity intensity and emissions per-unit of energy consumption (electricity generation). Results show that, with EUM, China, could save energy by 4.38 billion ton oil equivalences (toes) and reduce CO₂ emission by 16.55 billion tons; with IRSP, China, could save energy by 1.5 Btoes and reduce CO₂ emission by 5.7 Btons, during 2010–2030. To realize the massive potential, China has to reshape its economic structure and rely much on technology innovation in the future.     

Can envelope codes reduce electricity and CO2 emissions in different types of buildings in the hot climate of Bahrain?

The depletion of non-renewable resources and the environmental impact of energy consumption, particularly energy use in buildings, have awakened considerable interest in energy efficiency. Building energy codes have recently become effective techniques to achieve efficiency targets. The Electricity and Water Authority in Bahrain has set a target of 40% reduction of building electricity consumption and CO₂ emissions to be achieved by using envelope thermal insulation codes. This paper investigates the ability of the current codes to achieve such a benchmark and evaluates their impact on building energy consumption. The results of a simulation study are employed to investigate the impact of the Bahraini codes on the energy and environmental performance of buildings. The study focuses on air-conditioned commercial buildings and concludes that envelope codes, at best, are likely to reduce the energy use of the commercial sector by 25% if the building envelope is well-insulated and efficient glazing is used. Bahraini net CO₂ emissions could drop to around 7.1%. The simulation results show that the current energy codes alone are not sufficient to achieve a 40% reduction benchmark, and therefore, more effort should be spent on moving towards a more comprehensive approach.     

Implementation of energy efficiency standards of household refrigerator/freezer in China: Potential environmental and economic impacts

Due to the rapid economic development, living standards in China are improving fast. Chinese families are having more household electrical appliances, among which refrigerators are indispensable. Energy consumption of refrigerators is huge in China and causes environmental concerns. China has issued the national energy efficiency standards of household refrigerators, GB12021.2-2003 and GB12021.2-2008 to promote high-efficiency refrigerator production and use. This study evaluated the impacts of the standards on the environment, manufacturers and consumers over a long-term period of 2003–2023. It first evaluated the potential electricity conservation and GHG emission reduction resulting from energy efficiency improvements driven by the standards. Next, manufacturers’ technological and economic concerns about complying with the standards were discussed. Some efficiency improving design options were considered and the resulting increases in manufacturing cost and retail price were estimated. The return of consumers from invest in efficiency was analyzed based on lifecycle cost saving of the improved models. The economical viability of the standards was then evaluated by national consumer costs and benefits. Results showed that the considered efficiency standards will potentially save a cumulative total of 588–1180 TWh electricity, and reduce emission of 629–1260 million tons of CO₂, 4.00–8.04 million tons of SO_x and 2.37–4.76 million tons of NO_x by 2023, depending on sale share of models by efficiency. In a more environmentally optimal case (75% sale share of high-efficiency models), the national consumer benefits are 121 billion RMB (discounted), with the benefit/cost ratio of consumer’s expenditure being 1.45:1. However, the preference to high-efficiency models is substantial influenced by consumer’s expectation on return from the additional cost on efficiency.     

Scenario analysis of the energy demand and CO2 emission reduction potential of the urban transport system of Beijing through 2030

An assessment of the energy demand and the potential for sector-based emission reductions will provide necessary background information for policy makers. In this paper, Beijing was selected as a special case for analysis in order to assess the energy demand and potential of CO₂ abatement in the urban transport system of China. A mathematical model was developed to generate three scenarios for the urban transport system of Beijing from 2010 to 2030. The best pattern was identified by comparing the three different scenarios and assessing their urban traffic patterns through cost information. Results show that in the high motorization-oriented pattern scenario, total energy demand is about 13.94% higher, and the average CO₂ abatement per year is 3.38 million tons less than in the reference scenario. On the other hand, in the bus and rail transit-oriented scenario, total energy demand is about 11.57% less, and the average CO₂ abatement is 2.8 million tons more than in the reference scenario. Thus, Beijing cannot and should not follow the American pattern of high motorization-oriented transport system but learn from the experience of developed cities of Europe and East Asia.     

Scenario analysis of the energy demand and CO<Subscript>2</Subscript> emission reduction potential of the urban transport system of Beijing through 2030

An assessment of the energy demand and the potential for sector-based emission reductions will provide necessary background information for policy makers. In this paper, Beijing was selected as a special case for analysis in order to assess the energy demand and potential of CO₂ abatement in the urban transport system of China. A mathematical model was developed to generate three scenarios for the urban transport system of Beijing from 2010 to 2030. The best pattern was identified by comparing the three different scenarios and assessing their urban traffic patterns through cost information. Results show that in the high motorization-oriented pattern scenario, total energy demand is about 13.94% higher, and the average CO₂ abatement per year is 3.38 million tons less than in the reference scenario. On the other hand, in the bus and rail transit-oriented scenario, total energy demand is about 11.57% less, and the average CO₂ abatement is 2.8 million tons more than in the reference scenario. Thus, Beijing cannot and should not follow the American pattern of high motorization-oriented transport system but learn from the experience of developed cities of Europe and East Asia.     

Comprehensive evaluation of industrial CO2 emission (1989–2004) in Taiwan by input–output structural decomposition

Taiwan currently emits approximately 1% of the world's CO₂—ranking it 22nd among nations. Herein, we use the input–output (I–O) structural decomposition method to examine the changes in CO₂ emission over a 15-year period. By decomposing the CO₂ emission changes into nine factors for the periods of 1989–1994, 1994–1999, and 1999–2004, we have identified the key factors causing the emission changes, as well as the most important trends regarding the industrial development process in Taiwan. The 5-year increment with the largest increase of CO₂ emission was that of 1999–2004, due to the rapid increase of electricity consumption. From the decomposition, the industrial energy coefficient and the CO₂ emission factors were identified as the most important parameters for the determination of the highway, petrochemical materials, iron and steel, the commercial sector, and electric machinery as the major sources of increased CO₂ emission during the past 15 years. From 1989 to 2004, the level of exports and the level of domestic final demand were the largest contributors to the increase in the total increment of CO₂ change. During 1989–2004, the industrial energy coefficient and CO₂ emission factors, being minimally significant during 1989–1994, became extremely important, joining the domestic final demand and the level of exports factors as the major causes of the increase increment of CO₂. This indicates a heavy reliance upon high-energy (and CO₂) intensity for Taiwanese industries; therefore, continuous efforts to improve energy intensity and fuel mix toward lower carbon are important for CO₂ reduction, especially for the electricity and power generation sectors. Relevant strategies for reducing carbon dioxide emissions from major industries are also highlighted.     

Energy impact of indoor environmental policy for air-conditioned offices of Hong Kong

Air-conditioned office buildings are one of the biggest energy consumers of electricity in developed cities in the subtropical climate regions. A good energy policy for the indoor environment should respond to both the needs of energy conservation and the needs for a desirable indoor healthy environment with a reduction in carbon dioxide (CO₂) generation. This study evaluates energy implications and the corresponding CO₂ generation of some indoor environmental policies for air-conditioned office buildings in the subtropical climate. In particular, the thermal energy consumption in an air-conditioned office building was evaluated by the heat gains through the building fabric, the transport of outdoor fresh air for ventilation, and the heat generated by the occupant and equipment in the space. With the Monte-Carlo sampling technique and the parameters from the existing office building stocks of Hong Kong, the energy consumption profiles of air-conditioned office buildings in Hong Kong were evaluated. Energy consumption profiles were simulated for certain indoor environmental quality (IEQ) policies on indoor air temperature and CO₂ concentration settings in the offices, with other building parameters remaining unchanged. The impact assessment and the regression models described in this study may be useful for evaluation of energy performances of IEQ policies. They will also be useful for the promotion of energy-saving measures in air-conditioned office buildings in Hong Kong. This study presented a useful source of references for policymakers, building professionals and end users to quantify the energy and environmental impacts due to an IEQ policy for air-conditioned office buildings.